In a case of detecting an object using a radar device, a transmitting signal that is obtained from a transmission wave and a receiving signal that is obtained from a reception wave are mixed, and a relative distance and a relative speed of the object are detected from a peak signal that is detected by a frequency difference between the transmitting signal and the receiving signal. Here, the peak signal means a frequency spectrum having a signal strength that is equal to or higher than a predetermined value.
Further, in a case of detecting the object based on an FM-CW method, peak signals are extracted from an up period and a down period of a transmitting signal and a receiving signal, and a sensing point having parameters of the relative distance and the relative speed of the object is detected through combination of the peak signals in the up period and the down period. Here, the combination of the peak signals is determined by the speed of a vehicle having a radar device, the signal strength of the peak signal, and angle information. Further, a continuity determination process is performed to detect whether a recently detected sensing point is the sensing point of the same object as that of the past sensing point detected in the past and whether this sensing point has been continually detected multiple times, and if the sensing point has been continually detected over a predetermined number of times as the result of the determination, data of the latest sensing point is stored in a memory provided in the radar device.
Further, even in a case where the continually detected sensing point is not detected any further, an extrapolation process is performed to update the data of the sensing point under the assumption that the sensing point exists in a specific position from the position or speed information of the latest sensing point that was detected just before the sensing point is not detected any further, rather than to immediately delete the data of the sensing point from the memory (for example, see Japanese Unexamined Patent Application Publication No. 2004-53611). Further, if the sensing point, which corresponds to the sensing point updated in the extrapolation process, is detected through the next scanning, a process to store the corresponding sensing point in the memory as data of the latest sensing point by overwriting the data of the corresponding sensing point on the data of the sensing point updated in the extrapolation process. The data of the sensing point obtained through the extrapolation process is output to a vehicle control device that is targeted for vehicle control.